Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor having a rotatable hub with one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The rotor blades generally include a suction side shell and a pressure side shell typically formed using molding processes that are bonded together at bond lines along the leading and trailing edges of the blade. Further, the pressure and suction shells are relatively lightweight and have structural properties (e.g., stiffness, buckling resistance and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation. Thus, to increase the stiffness, buckling resistance and strength of the rotor blade, the body shell is typically reinforced using one or more structural components (e.g. opposing spar caps with a shear web configured therebetween) that engage the inner pressure and suction side surfaces of the shell halves. The spar caps are typically constructed of various materials, including but not limited to glass fiber laminate composites and/or carbon fiber laminate composites. The shell of the rotor blade is generally built around the spar caps of the blade by stacking layers of fiber fabrics in a shell mold. The layers are then typically infused together, e.g. with a thermoset resin.
Such rotor blades, however, are not without issues. For example, different blade components typically require different physical properties. More specifically, the blade root typically needs increased strength over the blade tip. Further, regions at the leading edge of the blade may need improved toughness for erosion protection. As such, conventional rotor blades must be constructed of materials that can withstand the highest anticipated loads of any single component. Unfortunately, such materials can be expensive and since conventional blades are typically constructed of two blade halves, the entire blade has to be constructed of the expensive material.
In addition, methods used to manufacture the rotor blades and/or structural components thereof can be difficult to control, defect prone, and/or highly labor intensive due to handling of the dry fabrics and the challenges of infusing large laminated structures. Moreover, as rotor blades continue to increase in size, conventional manufacturing methods continue to increase in complexity as the blade halves are typically manufactured using opposing mold halves that must be large enough to accommodate the entire length of the rotor blade. As such, joining the large blade halves can be highly labor intensive and more susceptible to defects.
One known strategy for reducing the complexity and costs associated with manufacturing rotor blades is to manufacture the rotor blades in blade segments. The blade segments may then be assembled to form the rotor blade. However, known blade segments are constructed similar to the blade halves and require complex interconnecting components to join the segments together. In addition, known joint designs do not provide for sufficient alignment of the blade segments, thereby increasing the amount of time needed to assemble the blade segments. Further, conventional segmented blades are typically heavier than conventional blades due to the additional joints and/or related parts.
Thus, the art is continuously seeking new and improved rotor blades methods of manufacturing same that address the aforementioned issues. Accordingly, the present disclosure is directed to modular wind turbine rotor blades constructed of multiple resin systems that are tailored based on the desired physical properties of each blade component.